From what I've seen, architects go to school, really arduous school, for years, after which they continue to work constantly, much more than 40 hours per week. I believe they get paid less than developers, have less job security -- and, yes, sit at a computer all day.
As I spend a lot of time working with architects, I can confirm that.
Architects spend all day in front of the computer, they click much more repetitively (a 12-hour CAD session will do wonders for your RSI), and they get paid less and find it harder to find a new job.
Then again, they do get to design cool buildings. Well, some of them do, anyway (a relatively small proportion, however).